The ability to produce and to understand materials with high thermal conductivities is becoming increasingly important. As microelectronic devices become smaller, faster and more powerful, thermal management is becoming a critical challenge in, e.g., microprocessors, light emitting diodes (LEDs) and high power radio frequency (RF) devices. Carbon based materials, including diamond and graphite, have long been recognized as having the highest thermal conductivities, κ, of any bulk material with room temperature (RT) values for diamond and graphite with naturally occurring carbon isotope mixtures of around 2000 Wm−1K−1. Other high thermal conductivity materials, such as copper are not even close, having κ four to five times smaller. However, diamond is scarce and its synthetic fabrication suffers from slow growth rates, high cost and low quality. Thus, there is a need to identify new materials with ultra-high thermal conductivities that are less expensive and are easier to fabricate than diamond based materials, as well as other materials used for thermal management applications.